1) Technical Field
The subject invention relates to vehicle door latch assemblies having both manual and power door locking features.
2) Description of the Prior Art
Vehicles, such as passenger cars, are commonly equipped with individual door latch assemblies which secure respective passenger and driver side doors to the vehicle. Each door latch assembly is typically provided with manual release mechanisms or lever for unlatching the door latch from the inside and outside of the vehicle, e.g. respective inner and outer door handles. In addition, many vehicles also include an electrically controlled actuator for remotely locking and unlocking the door latches.
As is commonly known, the release mechanisms may be actuated to lock the door latch assembly and prevent release of the outer door handle. However, a thief may break a window of the vehicle and reach inside to manually unlock the latch assembly by actuating the inner door handle. The industry has therefore developed door latch assemblies which have a xe2x80x9cdouble lockxe2x80x9d or anti-theft feature which also locks the inner door handle such that neither handle may be actuated to open the door.
The double lock or anti-theft feature is typically accomplished by the electrically controlled actuator and cannot be done manually. This helps ensure that the passengers are outside of the vehicle when the double lock feature is engaged. Examples of prior art door latch assemblies which incorporate a double lock feature are shown in U.S. Pat. Nos. 5,464,260 and 5,474,339. However, the prior art door latch assemblies incorporating the double lock feature have a number of deficiencies.
One primary deficiency relates to the electrical movement of the actuator between an unlocked condition, a locked condition and a double locked condition. A number of elements are actuated within the door latch assembly as the actuator moves between these conditions. The actuator is typically connected to an electric motor which controls the movements. The electric motor must be actuated a predetermined amount in order to move the actuator through the desired conditions. As appreciated, electric motors are susceptible to changes in temperature, moisture, and voltage such that the desired actuation of the electric motor may not be consistently and accurately achieved. Hence, it is desirable to have an electrically controlled actuator which incorporates at least three physical stops to ensure the proper movement of the actuator between the three different conditions.
A vehicle door latch assembly moveable between an unlocked condition, a first locked condition and a second locked condition. The door latch assembly comprises a support housing. A cover is mounted to the support housing and has at least one projecting abutment. A ratchet is pivotally mounted to the support housing and moveable or pivotable between a latched position and an unlatched position. A pawl is mounted to the support housing and has first and second ends with the pawl moveable between a blocking position wherein the first end abuts the ratchet to secure the ratchet in the latched position and a release position wherein the first end disengages the ratchet to permit the ratchet to pivot toward the unlatched position. A release mechanism is mounted to the support housing for selectively moving the pawl into the release position. A coupler is selectively coupled between the second end of the pawl and the release mechanism. The coupler moves between an engaged position aligned with the release mechanism and a disengaged position spaced from the release mechanism. A cam is rotatably mounted to the cover and includes a camming surface defining at least one stop for selective engagement with the abutment. A transfer element is mounted to the cam and engages the coupler for transferring the rotation of the cam into the movement of the coupler. A rocker is movably mounted to the cover for selectively engaging the camming surface of the cam. A first controller rotates the cam and moves the transfer element between a first position wherein the stop engages the abutment and the rocker engages the camming surface with the coupler engaged with the release mechanism for defining the unlocked condition of the door lock; a second position wherein the rocker engages the stop to prevent further rotation of the cam with the coupler disengaged with the release mechanism to define the first locked condition; and a third position wherein the stop engages the abutment and the rocker is released from the camming surface with the coupler disengaged further from the release mechanism to define the second locked condition. A second controller rotates the rocker to release the rocker from the camming surface during rotation of the cam from the second position to the third position.
Accordingly, the subject invention incorporates at least three separate physical stops for ensuring that the correct rotation of the cam and transfer element is achieved. The subject invention also incorporates a novel means of providing the second locked condition or double lock feature for the door lock assembly.